The present invention relates generally to the field of bearing dampers used to absorb and damp the deflections of bearing-supported shafts or other rotating apparatus. More particularly the invention provides a uniquely configured elastomeric bearing damper assembly which, for a bearing-supported shaft, provides highly linear lateral damping capabilities while additionally providing for resilient cushioning of axial shaft thrust loads.
The use of elastomeric material, such as rubber, neoprene or the like, to provide damping for various types of rotary bearings is well known in the bearing art. A conventional method of achieving such damping is to position an annular rotary bearing (such as a common ball or roller bearing) coaxially within an annular elastomeric member, and to restrain the bearing and damper so that lateral deflection of the bearing ("lateral", as used herein, meaning perpendicular to the bearing's axis) compresses a portion of its surrounding damper. In one common damper assembly the restraint of the bearing and damper member is effected by positioning annular flanges against the opposite side surfaces of the outer bearing race and the damping member, and placing the outer periphery of the damping member against appropriate supporting structure. The flanges permit radial movement of the outer bearing race, to thereby transmit to the damping member lateral deflections caused by imbalances in the rotating element supported by the bearing, but preclude appreciable axial deflection of the race.
Two inherent limitations and disadvantages are present in conventional bearing dampers of this type. First, it has been found that the radial compression of the elastomeric damping member provides only limited, and undesirably nonlinear, damping characteristics-especially in high rotational speed applications such as turbomachinery shaft support. Secondly, this conventional structure is incapable of absorbing axial thrust loads imposed upon the bearing without greatly increasing the bearing friction.
Accordingly, it is an object of the present invention to provide a bearing damper assembly which eliminates or minimizes the above-mentioned and other limitations and disadvantages associated with conventional bearing damper apparatus.